mei: revamp mei_data2slots

1. Move the mei_data2slots to mei_dev.h as it will be used
by the all supported HW.
2. Change return value from u8 to u32 to catch possible overflows
3. Eliminate computing the slots number twice in the same function

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c
index c86d7e3839a4..9a5e8c72628b 100644
--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -449,7 +449,7 @@ int mei_amthif_irq_write_complete(struct mei_device *dev, s32 *slots,
         struct mei_msg_hdr mei_hdr;
         struct mei_cl *cl = cb->cl;
         size_t len = dev->iamthif_msg_buf_size - dev->iamthif_msg_buf_index;
-        size_t msg_slots = mei_data2slots(len);
+        u32 msg_slots = mei_data2slots(len);
 
         mei_hdr.host_addr = cl->host_client_id;
         mei_hdr.me_addr = cl->me_client_id;
@@ -566,12 +566,13 @@ int mei_amthif_irq_read_message(struct mei_cl_cb *complete_list,
  */
 int mei_amthif_irq_read(struct mei_device *dev, s32 *slots)
 {
+        u32 msg_slots = mei_data2slots(sizeof(struct hbm_flow_control));
 
-        if (((*slots) * sizeof(u32)) < (sizeof(struct mei_msg_hdr)
-                        + sizeof(struct hbm_flow_control))) {
+        if (*slots < msg_slots)
                 return -EMSGSIZE;
-        }
-        *slots -= mei_data2slots(sizeof(struct hbm_flow_control));
+
+        *slots -= msg_slots;
+
         if (mei_hbm_cl_flow_control_req(dev, &dev->iamthif_cl)) {
                 dev_dbg(&dev->pdev->dev, "iamthif flow control failed\n");
                 return -EIO;